Seo Dong-Oh, Pang Min-Hee, Shin Maeng-Sik, Kim Hyun-Taek, Choi June-Seek
Department of Psychology, Korea University, 5-1 Anam-Dong, Seongbuk-Gu, Seoul, 136-701, Republic of Korea.
Behav Brain Res. 2008 Oct 10;192(2):264-8. doi: 10.1016/j.bbr.2008.04.011. Epub 2008 Apr 20.
We tested whether N-methyl-D-aspartate (NMDA) receptors in the dorsal hippocampus (DH) are critical for the acquisition of trace fear conditioning using conditioned hypoalgesia (CHA), decrease in pain reactivity, as the conditioned response (CR) instead of commonly used freezing. Infusions of the NMDA receptor antagonist, DL-2-amino-5-phosphonovaleric acid (APV) into DH prior to conditioning resulted in impaired CHA, measured with the radiant heat tail flick test, only in the trace-conditioning group when they were tested during the trace interval. The same infusion had no effect on CHA in the delay-conditioned animals. The results support that NMDA receptors in DH are critically involved in associating the CS with the US across a temporal gap. In addition, temporal specificity of the CR was revealed as CHA was induced only in the temporal vicinity of the US used for the training.
我们使用条件性痛觉减退（CHA），即疼痛反应性降低，作为条件反应（CR），而非常用的僵住反应，来测试背侧海马体（DH）中的N-甲基-D-天冬氨酸（NMDA）受体对于痕迹恐惧条件反射的获得是否至关重要。在条件反射训练前，向DH中注入NMDA受体拮抗剂DL-2-氨基-5-磷酸戊酸（APV），当在痕迹间隔期对动物进行测试时，仅在痕迹条件反射组中，通过辐射热甩尾试验测量发现CHA受损。相同的注入对延迟条件反射动物的CHA没有影响。结果支持DH中的NMDA受体在跨越时间间隙将条件刺激（CS）与非条件刺激（US）建立联系中起关键作用。此外，CR的时间特异性表现为仅在用于训练的US的时间附近诱导出CHA。
